In the course of manufacturing disposable absorbent articles, such as diapers and sanitary napkins, it is common to detect defect or imperfect articles and discard them from the production process. Though not suitable for sale, these waste products may contain materials, which are too valuable to be thrown away. Instead, it may be desirable to retrieve certain materials from the defect product. Especially, it is desirable to regain the superabsorbent polymer particles typically comprised in disposable absorbent articles.
Today, most disposable diapers use absorbent cores with superabsorbent polymer particles intermingled with pulp fibers (so-called “airfelt”), such as cellulose fibers. In these diapers, the superabsorbent polymer particles are largely held in place by the surrounding pulp fibers. The superabsorbent polymer (SAP) particles may therefore be retrieved by shredding the articles and shaking the SAP particles out e.g. via vibration, freeing the particles from the surrounding pulp fibers.
However, moving to absorbent articles wherein the absorbent cores are free from airfelt or wherein the absorbent cores contain only small amounts of airfelt, the SAP particles have to be immobilized by different means, as they can no longer be held in place by surrounding pulp fibers. One way to immobilize the SAP particles within the absorbent core is by using adhesives. These adhesives, though used in small amounts relative to the amount of SAP particles, closely adhere to the SAP particles. Apart from attaching the SAP particles to each other, the adhesives also adhere the SAP particles to a carrier substrate, such as a nonwoven web. Thereby, the particles cannot simply be shaken out to recycle them.
Thus, it would be desirable to have a method for separating SAP particles from the adhesives in order to regain the SAP particles. The particles can then be re-used for the manufacture of disposable absorbent articles.